I have a 95 LT-1 and yesterday it overheated. On Friday I noticed the AC was not putting out cold air and last night I drove the car home as I was going to take it to a friends shop to see if a recharge would fix the AC. On the way home, the "Check Gauges" light came on and the water temp gauge was pegged, I did not check the numerical readout. I pulled over and let the car cool down and eventually got home by driving a little and then letting it cool a little. The heater was blowing a lot of hot air.

Today, I checked the reservoir and it was full of coolant. I ran the car and with the AC on, the fans were on and the AC would engage and disengage on about 5 second intervals. With the AC off, the fans were off until the coolant temp (numerical) was around 220, then around 235, the fans got a lot louder, the temp continued up to 244. At that point, the analog gauge was pointing to 260.

The hose to the top of the radiator was hot and the one from the bottom was hot but not quite as hot. I checked the front of the AC condenser and it is clear. As good as I could look at the front of the radiator it looked clear.

The car always seemed to run about 205, but I cannot say that I checked that recently. It seems to be a fairly sudden problem. It has been about 30,000 miles since I replaced the water pump and thermostat and flushed the coolant. It does not have dex cool in it.

So my first thought is the thermostat is stuck. Any other ideas?

 

dumb question. what about the serpentine belt ? is it driving the components ?

just because you replaced the water pump doesn't mean it is still working correctly.

 

How many miles on your car? You may need to remove the radiator and clean all the fine sand like particles from it. My 96 was full of them and it only had 58000 miles. I used my compressor and shop vac, alternating them, to clean it. You will need to clean the AC condenser also. I would cover your engine when doing the condenser. Your AC may need Freon. Your compressor should stay on and not cycle on and off so quickly with the AC on. Did you take out the knock sensors on the engine block when you last flushed? If not, mixing dexcool and regular green antifreeze can gum up your system. Be Well! Kevin

 

https://www.corvetteforum.com/forums...peratures.html


Hello, the 92-96 Vettes do not use the belt to drive the water pump

 

Yes, but it does drive the A/C compressor. However, yes I forgot about that since you were so gracious to have point it out. And yes, just because the pump was replaced, doesn't mean it still is working correctly. (I actually have the tools to service the waterpump/front end of the LT1, guess I am getting CRS).

 

The water pump is a possibility but the heater was working, so it appears to be circulating coolant through the heater core.

The car has 102K on it and I looked at the front of the condensor hoping to find a plastic bag, but it looked clean. Your point that it should be taken out and cleaned is well taken and I plan to do that. This problem seems to have developed suddenly so I am thinking that even in its uncleaned state, it was more than adequate a week ago. I purchased a new thermostat and may put it in tomorrow. Problem is that the car is at home and that is not where my shop is, so doing something even as simple as changeing the thermostat is a challenge.

[QUOTE=PLRX;1601725454]https://www.corvetteforum.com/forums...peratures.html

This is a great link, lots of good information there.

 

[QUOTE=skybolt31;1601726219]The water pump is a possibility but the heater was working, so it appears to be circulating coolant through the heater core.



The car has 102K on it and I looked at the front of the condensor hoping to find a plastic bag, but it looked clean. Your point that it should be taken out and cleaned is well taken and I plan to do that. This problem seems to have developed suddenly so I am thinking that even in its uncleaned state, it was more than adequate a week ago. I purchased a new thermostat and may put it in tomorrow. Problem is that the car is at home and that is not where my shop is, so doing something even as simple as changeing the thermostat is a challenge.

You have to take it out to clean. You can't see blockage until you do

 

I had similar issues with top hose being hot and bottom hose being not so hot. In my case it was indeed the thermostat not opening fully. Was a brand new AC Delco stat. I did not have temperatures as hot as you, though.

 

Personally? I would check the simple and obvious first. Take the thermostat out and drop it into a pot of water. But first, bring the water to a boil. Set it aside and drop the thermostat in. If it doesn’t open there is your culprit. If you have to put it back in remember...it always points to the radiator.

 

you may have a collapsed radiator hose.

 

Yes this is usually invisible to the naked eye?

 

Usually it happens when the engine is revved. Look for the lower hose from the radiator to deform as the water pump suction starts to increase as the engine rpm's climb.

 

Flushed out radiator and changed thermostat, No change, but temp on analog gauge is 260, digital readout on dash is 244, on ECM through scan tool is 216. Ordered two new temperature sensors to see which one is lying.

 

Good move. How is the fan clutch?

 

I am too having overheating issues. I've cleaned the radiator and the A/C condenser.
I was wondering if I need to change the waterpump. What special tools are required to do that?

 

Did you take it out to clean it?

 

Say what?



None. It's very easy to remove.

 

Just be extremely careful not to get any coolant on the Optispark distributor.

Also- see if you can get peek at the front of the radiator. I found a little access through the corners of the top shroud with a bright flashlight.

 

So my thermostat was replaced and radiator flushed, same problem, temp on the ECM was 216 when the gauge was 260, replaced both sensors, now it works fine.

 

Yes. I did take out the radiator and cleaned it with air compressor and garden hose. Got a lot of material out of it. Definitely runs cooler. About 25 degrees. I was asking about special tools to change waterpump. Are there any special tools needed to do this?